Internal-combustion engine



June 7,1927. 1,631,704

E. SOKAL v INTERNAL COMBUSTION ENGINE Original Filed July 9, 1925 4 a 'A 4 A INV N TOR.

Fatented June 7, 1927 man STATES PATENT OFFICE.

EDWARD SOKAL, OF NEW YORK, N. Y., ASSIGNOR T AMERICAN KATALITE GOR- EO'IION, 0F BROOKLYN, NEW YORK, A CORPORATION OF DELAWARE.

INTERNAL-COMBUSTION ENGINE.

original application filed July 9, 1925, Serial No. 42,583, and in Canada July 6, 1925. Divided. and this application filed December 18, 1926. Serial No. 155,586.

This invention relates to internal combustion engines, and more particularly to engines of the relatively high compression t e. e

ft is an object of the invention to provide within the combustion chamber of such an engine, substantially stable chemicalmeans possessing the property of counteracting the phenomena and disadvantageous results of detonation, or knocking, which means may be referred to as a detonation counteractant.

Another object of the invention is to provide a beneficial material for location Within a combustion chamber which, possessing the property of decreasing the tendency to carbon deposition and heat loss, enhances the efiiciency of engine operation.

A further object of the invention is to provide a coating material for the purposes recited, among others, and which may be 'readily disposed within the. interior of a combustion chamber and the effective properties of which will not be permanently affected by the conditions within the combustion chamber.

This application is a division of my copending application for improvements in internal combustion engines, filed July 9, 1925, Serial No. 42,583.

At the present time the phenomenon of detonation, or knocking, during the operation of internal combustion engines is of much interest because, other conditions being equal, it is more pronounced with .engines of high compression ratios. Accordingly this tendency to detonate with a given fuel becomes practically a limiting factor for improvement in the thermal efficiency and power output through an increase in the compression -ratio. This is particularly the case with the constant volume cycle type of engine which is used almost exclusively in automobiles and in aeroplanes and also to a considerable extent in small marine and stationary engines.

erative before these other limiting factors exert their influence. In order to obviate i or decrease detonation, it has been suggested that various materials be added to the fuel. Some of these appear to have a favorable action but show the interesting characteristie that if they are added to the fuel in excess of very small quantities, they cause a decrease rather than an increase in power output.

Various tentative explanations have been oifered for the phenomenon of detonation. It 1s my view that detonation, or knocking 1n lnternal combustion engines is mainly due to a decomposition or breaking down of the unburned fuel, or in other Words, to the dissociation of the larger molecules of the fuel under the influence of heat' and pressure into a greater number of smaller molecules whereby there is caused a sudden rise of pressure. This rise of pressure may not be indicative of the true pressure condition within the whole body of the fuel-air mixture, but is rather in the nature of a localized impact. This view is supported by the following considerations; first, the detonating tendency of various fuels is ractically a function of their thermal sta ility, for example, the tendency to detonate decreases in the following order: kerosene, ordinary and hydrogen, and the thermal stability increases in the same order; second, the indicator diagram of detonating engines shows a very rapid rise of pressure which lasts only a very short period of time, is followed by anequally rapid decline, frequently occurs several times at the beginning of the expansion stroke, the peaks becoming smaller each time, and these rises of pressure are of such short duration that the corresponding pressure volume area is too small to represent an appreciable amount of useful work' and hence they manifest themselves as destructive impacts;third, detonation is accompanied by lost power, deposition of carbon and great loss of heat to the water jacket, which loss of power and deposition of carbon may be considered natural results from the decomposition of the fuel, and the loss of heat to the water jacket is probably due to radiation caused by glowing'particles of carbon and to the impacts; and, fourth, it has been shown that various factorswhich cause an-increase in the rapidity effect in counteracting detonation.

' combustion chamber of astandard internal combustion engine a coating material containing a substance, or substances, which has a low melting point, or which passes into another form at a relatively slow temperature. Detonation being due to a thermal decomposition of the fuel, then by bringing the fuel-air mixture into contact with a de-- tonation counteractant, the decomposition may be inhibited either by lowering the temperature of the unburned. fuel; by catalyzing negatively the reaction of decomposition, or it may be by the prevention of a positive catalytic effect on the reaction of decomposition by the walls of the combustion chamber. It may be that these efiects are combined and in the present--state of knowledge, it would be very difiicult, if not impossible, to separate them quantitatively.

While it is believed that the effect roduced is primarily a thermal skin e ect, resulting from a cooling of the fuel-air mixture by a low meltin substance or a substance which acts en othermically without melting, as for example, the formation of, an allotropic substance, it is to be considered that the effect may be enhanced or diminished by other characteristics such as conductivity, catalytic properties, reactivity, with particular reference to capability of reaction with oxygen and other components of the gaseous mixture, etc. It must furthermore be borne in mind that such a thermal molecular skin effect of the coatin resulting a counteracting of its decomposition, may

also influence the rapidity of' combustion, and likewise any negative catalytic efiect on the decomposition reaction may be combined with a negative catalytic effect on the combustion. However, such characteristics are probably purely accidental coincidences and are not fundamentally of. concern in connection with 'my invention, in accordance with which detonation may be counteracted by fixedly disposing within the combustion chamber of an internal combustion engine a properly adapted permanent solid substance.

It was expected'and confirmed by experiments that an extreme cooling eifect on the fuel-air mixture would interfere with the functioning of the engine if not render it entirely inoperative, while the same effect, if

utilized to a much smaller degree, would result in counteractingdetonation without any functional"interference. I

In practice, the present invention com- 'prises the utilization Within a combustion tial reaction with the constituents of they gaseous mixture. Furthermore, the coating material. may comprise antimony in admixture with a-suitable binder; for example, a coating material may consist of subdivided antimony and a silicate binder. The proportions of active substance to hinder may be varied according to requirements, and it has i been found that a satisfactory result is produced when a mixture containing three parts by weight of subdivided antimony to one part by Weight of a silicate is employed. Application may be accomplished by cleaning the desired surface area, coating such area with the detonation counteractant and baking or setting. This procedure may then' be repeated until the desired number of coats has been applied. 'Thefactive sub-.

stance in the mixture, even though melted,

is firmly retained, does not detach itself, and is so intimately in contact with the binding material, and in some cases chemical combination may actually take place, that itsv reactivity with the gaseous mixture is reducedto a minimum.

The amount of detonation counteractant to be applied in a particular type of engine may be'readily determined by suitable tests indicating the proper surface area to be coated in order to obtain eflicient operation. The detonation counteractant is fixedly dis osed within the combustion chamber an its disposition is susceptible of being accomplished-in a variety of ways. Its relative location within the combustion chamber may also be chosen as desired. For ex-.

mixture may be regulated when desired.

Utilization of the detonation counteractant on account of its endothermic properties produces a marked cooling efiect entire 30 fuel-air mixture, so that decomposition of the unburned part is retarded if not prevented. in other words, it prevents the unburned particles in the flame from'reaching a temperature sufficiently high to cause their decomposition before actual ignition. If this effect were to be availed of to its fullest extent, it would also prevent propagation of the flame, and accordingly proper functioning of an engine. An experiment in which a large part of the surface of a cylinder head was covered with an active substance alone in a finely subdivided condition, illustrated thecorrectness of the foregoing statement in that it rendered the engine inoperative. This experiment speaks rather against an explanation by catalyticaction. It is necessary therefore to apply the active substance as a coating material to only a portion of the interior of the combustion chamber or if it is desired to cover a larger area, this active substance is to be attenuated through admixture with a binder which is inert.

I have shown by a series of experiments made under actual road conditions with a special high compression Ford cylinder head which was used on the one hand without applicationof a detonation counteractant and on-the other, with the application of a detonation counteractant that under heavy load conditions, as for example, hill climbing, the uncoated head detonated at practically all spark and throttle positions, while with the cylinder head coated, the engine operated without detonation with a wide open throttle and a fairly advanced spark. These tests.

were repeated and Varied many times and the results were concordant and satisfactory, evidencing an increase in power output and a counteracting of the conditions to which detonation is due, from which it follows that the thermal efiiciency may be increased by an increase in the compression ratio without the attendant disadvantages of detonation.

The drawing is a partly sectional view exemplifying a form of the invention wherein a permanent detonation counteractant, such as contemplated by the invention, is fixedly disposed within the combustion chamber of an internal combustion engine in the form of a coating applied to the exposed surfaces of the piston head and the exhaust valve, the

hottest points on the Walls of the chamber.

In this exemplification, a cylinder block 1, together with a high compression cylinder head 2, provides a combustion chamber 3 into which the contacts 4 of a s ark plug 5 extend. A portion of the wal of the combustion chamber is provided by the piston head 6 on the surface of which is a coating 7 containing antimony. Another portion of the wall of this chamber is provided by the surface of an exhaust valve 8 on which there is also provided a coating 9 containing antimony.

The detonation counteractant preferabl comprises a substance or substances whic are nonabrasive, and accordingly no injury to the cylinder walls will result in the event that a portion should become detached.

Among the advantages arising through the utilization of the detonation counteractant, mention may be made of the following lack of detonation or knocking, lower fuel consumption, more flexible operation of the engine, decrease in carbon deposition and an increase in the thermal efliciency, particularly in connection with the use of high compression engines.

I It is to be understood that the invention in its broad sense is for the employment in the combustion chamber of an internal combustion engine of a material possessing the property of counteracting detonation, which material ma be used alone or in admixture with a suita le binder, and to permit the redesigning of engines having higher compression ratios.

\Vhile the theory herein presented offers a basis for an understanding of the manner in which the detonation counteractant may function, and while it is supported by known facts, it is to be understood, of course, that the operativeness and racticability of the invention is not depen ent upon or limited in any way by the correctness of such theory.

Since certain changes may be made in the detonation counteractant above described and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. i

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an internal combustion engine, the combination of a combustion chamber, and a detonation counteractant comprisin anti- Lnony and fixedly disposed within sai cham- 2. In an internal combustion engine, the combination of a combustion chamber, and a coating fixedly disposed on certain of the walls of said chamber, said coating including antimony.

3. In an internal combustion engine, the combination of a combustion chamber, and a coating permanently affixed to certain of those portions of the walls of the chamber which are hottest during engine operation, saidcoating including antimony.

4. In an internal combustion engine, the

combination of a combustion chamber, a permanent detonation counteractant fixediy disposed within said combustion chamber, said detonation counteractant comprising anti- 5 mony, and a binder. I

5. Inan internal combustion engine, the combination of a combustion chamber, and

a coating fixedly disposed on certain of the Walls of said chamber, said coating comprising an intimate admixture of sub-divided w antimony and a silicate.

In testimony whereof I afiix my signature.

EDWARD soKAL. 

